Could Quantum Dots improve night viewing?
Apr 7, 2016
Ray Soneira, the display expert behind DisplayMate, just posted a great, in-depth piece that looks at Apple's new Night Shift feature. Night Shift is designed to reduce blue light coming out of a device's display at night. Studies have shown that exposure to blue light in the 460-480nm wavelength range may affect our sleep cycle. So the thinking is that a reduction in blue may improve your sleep, even if you tend to stay up late reading on your device.
According to Ray, Night Shift works as advertised in terms of blue light reduction but with one big drawback- reducing the amount of blue light in the display gives it a yellowish appearance that makes photos look old or stained.
Quantum dot spectrum of a Vizio R65 vs an iPad Pro 9.7. The Vizio delivers a full-color viewing experience without 460-480nm blue while maintaining white balance for a great nighttime viewing experience.
Ray suggests that Quantum Dots may offer a better alternative for night viewing. Using data from the Quantum Dot-equipped Vizio R65, Ray shows that Quantum Dot displays can be tuned to reduce the amount of blue energy in the troublesome 460-480nm range just as much as Night Shift, while still delivering fantastic picture quality:
For LCDs that will mean switching from White LED Backlights, which produce rolling broadband spectra, to Backlights that include sharp Primary spectra using tunable Quantum Dots, fluorescent films or discrete Blue, Green and Red LEDs.
It turns out that a current model Vizio R65 TV with Quantum Dots that produce a very wide Rec.2020 Color Gamut already demonstrates how this is done. In Figure 3 below, the Vizio R65 spectrum (courtesy of Nanosys, which makes the Quantum Dots) has about 35% less Blue light in the 460-490nm region (for the same total Blue Luminance) as the iPad Pro with a standard White LED Backlight, and it remains fairly low up through 510nm. Again, this comparison applies to all LCDs with White LED Backlights, not just the iPad Pro 12.9.
The improvement with Quantum Dots is comparable to the improvement using Night Shift on the iPad Pro 12.9 that we examined above, but without a strong Yellow color cast, and maintaining the same full Color Gamut and White Point.
For more on this topic check out this great follow-up post by John Seymour (aka John The Math Guy). John takes a closer look at the the physiological reasons certain wavelengths of blue light might keep us up at night- good stuff!
Photo Credit for "Person looking at smartphone in the dark": Japanexperterna, licensed under CC